A novel trophic cascade between cougars and feral donkeys shapes desert wetlands (2022) Lundgren et al., Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.13766

Image credit: CHUCAO, CC BY-SA 3.0, via Wikimedia Commons

The Crux

Trophic cascades (see Did You Know?) are an important part of many ecological systems. However, most of the world’s large predator species were lost around 10,000 years ago (potentially due to human impacts), thus limiting the role that predators could play in driving trophic cascades. Though large predators were lost, many large herbivores are still around, which means it is difficult for a smaller predator to take down/consume these herbivores, much less have an effect large enough to drive a trophic cascade.

In the United States, large felines such as cougars (Puma concolor) are known to predate large equid species (such as feral horses or donkeys), but much of the ecological literature assumes/claims that cougars do no exert a strong enough pressure to consider them “significant” predators of these equid species. Specifically, some reports state that these species don’t have any natural predators, and other reports echo the claim. Today’s authors report on a novel trophic cascade between the cougar, feral donkeys (Equus africanus asinus), and wetland vegetation.

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